一种非正交多址接入下行链路信号检测方法

非正交多址接入（non-orthogonal multiple access，NOMA）下行链路存在严重的多址干扰。软解调-串行干扰消除（successive interference cancellation，SIC）检测方法是一种性能较好的信号检测方法，但是接收机的复杂度比较高。考虑到软解调算法对其他用户信号的信号特征信息并未充分利用，提出一种基于软解调算法改进的联合检测算法，该算法直接利用多用户叠加信号的联合星座图计算用户信号信息比特的软信息，不需要对干扰信号进行检测和重构，可以降低接收机的复杂度。仿真分析表明，与软解调-SIC检测方法相比，联合检测方法在性能损失不超过1．5 dB的情况下，可以将接收机的复杂度降低一半。

A method of detecting signal for downlink non-orthogonal multiple access

The downlink of non-orthogonal multiple access ( NOMA) exists serious multiple access interference. Soft demodulation-SIC(successive interference cancellation) is a kind of signal detection method with better performance, but the complexity of the receiver is relatively high. Considering the soft demodulation algorithm doesn''t make full use of the signal feature information of other users''signal, this paper proposes a joint detection algorithm based on improved soft demodulation algorithm, and this algorithm directly utilizes the joint constellation of multiuser superimposed signal to calculate soft information of user signal information bits, doesn''t need to detect and reconstruct the interference signal, and therefore it can reduce the computational complexity of the receiver. Through simulation analysis, the joint detection method can reduce the computational complexity of receiver by half under the circumstance of the performance loss of no more than 1. 5 dB, as compared with the soft demodulation-SIC detection method.